Staff at The Three Legged Cross in Forest Road were battling to get the water out of the pub after a nearby river burst its banks.
Owner Nicky Clark said: "It happened on Christmas Eve too, but this time it is 10 times worse. The car park is completely flooded and we've got about four inches of water in the pub."
Passing cars were driving through flood water directly outside the pub today, causing it to surge nearer the business.
Nicky added: "We were able to stay open on Christmas Eve but this time it is too much.
Obviously we have lost revenue and I still need to pay the staff, but the cellar is at the back of the building, so it has not affected the stock.
If there is more rain overnight, we may have to close tomorrow too."